1. Field of the Invention
The present invention relates to a vehicle control device mounted in a vehicle for enabling initiation of a driving source such as an engine according to authentication with a portable unit such as an electronic key.
2. Description of the Related Art
In recent years, a slot key has become popular in place of a mechanical key which is inserted into a key cylinder provided in an instrument panel of a vehicle and is turned to initiate an engine. After a user just inserts the slot key, such as an electronic key, into a slot, for example, provided in the instrument panel, or inserts the electronic key therein and simply presses a push button or the like, intercommunication between the electronic key and the vehicle is performed to authenticate the key, allowing the engine to be initiated or the like.
However, the device adopting the slot key is simply configured to have the electronic key inserted into the slot. Countermeasures are not made to prevent the electronic key from dropping out due to the rotations of the key cylinder when the vehicle is moving not like the mechanical key. In this regard, there has been known an art which adopts a key interlocking technology in the slot key device to prevent the electronic key from dropping out of the slot when the vehicle is moving. For example, there has been disclosed an art in which the key interlocking is fulfilled in conjunction with an electrical power supply from a device related to the initiation of the engine (for example, refer to Japanese Patent Laid-open No. 2005-248902, hereinafter referred to as Patent Document 1).
The slot key device disclosed in Patent Document 1 is provided with a solenoid configured to prevent the electronic key inserted in the slot from being removed when a key-insertion detection switch detects the electronic key has been inserted in the slot and a battery is supplying at least one of an ignition electrical power to an ignition device and an accessory electrical power to an accessory device. This slot key device supplies the electrical power to the solenoid via a diode in accordance with the electrical power supplied to the ignition device and the accessory device from at least the battery. Thereafter, in accordance with the electrical power supplied to the solenoid, a plunger protrudes into the slot and engages with an engagement recess provided in the electronic key to prevent the electronic key from being removed.
However, it is desired that the electronic key can be removed out only in such a situation that the vehicle is prohibited from driving (drive-prohibited state) in consideration of the fundamental purpose thereof. In this regard, the electrical power supplied to the ignition device and the accessory device may not appropriately match the situation. In other words, for example, the drive-prohibition of the vehicle is released when the engine is initiated; however, it is presumable that the electrical power may not have been supplied to either the ignition device or the accessory device. Therefore, for the device mentioned in Patent Document 1 in which the electronic key is locked in conjunction with the electrical power supplied to the ignition device and the accessory device, it is possible that the key is not locked in a situation where the key is desired to be locked.
Further, according to the device of Patent Document 1, it is configured that when the engine is initiated, for example, the electrical power supplied to the solenoid is defined in accordance with the electrical power supplied to the ignition device from a time when the ignition device is turned on to a time when the accessory device is turned on by the engine. Thereby, if a large amount of electrical power is supplied to a starter motor, for example, in addition to the ignition device when the battery is of low power, the electrical power supplied to the ignition device would be insufficient, and consequently, the electrical power supplied to the solenoid would be insufficient. In other words, even though the ignition device is turned on, the key cannot be prevented from being removed for sure. Thus, in the device disclosed in Patent Document 1, the electrical voltage varies due to the low power of the battery, which varies the condition preventing the electronic key from being removed. Thereby, it is possible that the electronic key is not locked in a situation where the electronic key is desired to be locked.